In the end, it was Groupon's fear -- and not its greed -- that apparently derailed a roughly $6 billion buyout from Google (Nasdaq: GOOG).

Business Insider's Nicholas Carlson is reporting that Groupon was demanding a chunky termination fee to protect itself from deal-stomping antitrust regulators. Once Google balked at the lofty insurance sum, the two companies went their separate ways.

The mutual separation makes sense.

It's easy to see why Groupon's board wanted to make sure that it wasn't wasting its time. Google had to jump through plenty of hoops to get its DoubleClick merger approved, and this summer's deal to acquire ITA Software is still facing stiff antitrust scrutiny. If regulators set up barriers over a potential $700 million acquisition of the online travel specialist, how can anyone be sure that the world's biggest search engine will be able to pull off a $6 billion deal for the undisputed champ when it comes to social coupons.

However, one also has to consider Google's perspective. Hefty breakup fees will be a major part of any future needle-moving negotiations, so it couldn't have been shocked at the request. Then again, if Groupon feels that its value may diminish after a prolonged merger process that isn't allowed to go through -- meaning that it believes it may be worth less than $6 billion a year from now instead of more -- it's easy to see why some would see an unusually large breakup fee request as a warning flag.

Maybe this is it. It's closing time for Google's billion-dollar swallows.

What about Groupon, though? Will someone else come in and scoop up Groupon? It's highly unlikely to happen at anywhere near $6 billion, especially now that they know that Google is too wrapped up in red tape to raise a bidding card.

Yahoo! (Nasdaq: YHOO) was rumored to be interested two months ago, but at roughly half of today's $6 billion chatter. eBay (Nasdaq: EBAY) and Amazon.com (Nasdaq: AMZN) are other obvious landing places given their market leadership positions in e-commerce, and they both have just enough cash and short-term investments on their balance sheet to pull a deal off.

However, the more logical buyer would have to be Microsoft (Nasdaq: MSFT). It's been surprisingly losing money in its online operations, and snapping up Groupon with its thick margins would remedy the shortfalls while also giving folks a daily reason to check out Bing. The rub here is that Mr. Softy is also no stranger to regulator shakedowns.

What's a Groupon to do? Easy. Go public and settle the valuation quandaries once and for all.

Have you ever used Groupon or a Groupon-esque site for a deal? Share your thoughts in the comment box below.